The Sansa Express keeps perfect track of the song position when turned off manually, but that seems to be the only time it keeps track of where it left off. If you pause it long enough for it to go into sleep mode or play through to the end of a folder or song list so it goes into sleep mode it restarts the next time from where it did the previous time instead of from where it left off. This is VERY annoying for long podcasts and audio books.
I enjoy listening to podcasts and audio books while doing chores, but at times I need to pause for a bit (to answer the phone, so the sound of the garbage disposal doesn’t make me miss out on what is being said, etc). Most times the pause is short enough that I can unpause before the Sansa Express has powered down, but sometimes the reason I needed to Pause takes longer than expected and the unit powers down on me, causing me to lose my place. This is VERY frustrating when listening to long files (30min to 90min is VERY common for what I listen to), causing me to waste time trying to find my place again. The Sansa should bookmark where it left off any time it is paused, powers down, or changes mode (such as switching to FM Radio).